Garden Plants and Snow

A winter storm visited large parts of North America this week, and we hope that you’re all safe and warm. The unusual winter weather—including snow on the Gulf Coast of the United States—got us thinking about how this type of weather affects our plants. Snow is an interesting phenomenon in its own right, and the way it interacts with plants is more interesting still. So put on some mittens and grab a snow shovel; let’s dig in and learn more about garden plants and snow!

Does Snow Protect Plants from Cold/Freezing?

Let’s start with a common gardening question: does snow protect plants from cold temperatures or freezing? Well, as it turns out, yes it can if conditions are right. Snow is relatively light and fluffy compared to other forms of precipitation, meaning that it captures air in tiny spaces between its flakes. These air spaces act as insulation the same way a wool sweater does: they prevent heat from moving through and keep it trapped, in this case against the ground and the plants on the ground. Dry powdery snow has the strongest insulating affect—wet snow, slush, and sleet are all far less effective and can actually wick heat away from the ground and back into the cold air.  New snow also works more efficiently than old snow, which compacts and loses its air pockets.

No less a publication than the Farmer’s Almanac recommends piling extra powdery snow on flower beds, around shrubs and bushes, and around the base of young trees to help insulate them from particularly cold snaps. We’ve never used this technique ourselves, but we’d love to know more about it if any of you have used it.

Snow on Tree Branches and Boughs

Snow may be a good insulator, but not every effect snow brings to your plants is a good one. Heavy snow can  build up on the branches and boughs of trees and shrubs. While larger trees and mature landscaping shrubs may be strong enough to support the weight of snow until it drops away or melts, heavy wet snow can break the branches of smaller trees, shrubs, and bushes. The solution is to gently shake the branch in question—or brush it with a broom—and move the snow away before it can build up and add too much weight. Be careful while you do this and make sure you don’t dump snow on yourself! A face full of wet snow is no fun, and worst case you could become temporarily buried in a larger dump of snow.

Road Salt and Your Garden Plants

Many places spread salt on the roads before a winter storm or after the snow has fallen. Salt lowers the freezing temperature of water and melts snow and ice away. While this is great for drivers and keeps our roads safe, it can be bad for garden plants located near streets or roads that have been treated with salt. Too much salt in the soil is toxic to plants and can kill them, so it’s important to take some steps to protect your plants if your municipality is salting the roads. You can set up barriers using burlap, sheets of cardboard, or snow/silt fence to keep the salt away from your soil and block salt spray from reaching your plants. Plant covers can work well for this—make sure you cover the entire plant and the soil around it—or you can just wrap the plant itself in fabric like burlap. When the snow passes, give the soil around your plants a deep watering to flush the soil and remove salt buildup. If mulch has been exposed to heavy salting, it may be time to replace it. We know that’s a lot of work, but better safe than sorry when it comes to the health of your landscaping plants.

Snow Helps Your Soil

We’ve written about this before so we won’t go into much detail here, but snow can actually be good for your soil. In addition to providing much needed water, as snow forms and falls in the atmosphere it captures atmospheric nitrogen and then deposits in in the soil as it melts. This helps plant growth and soil health, so much so that in parts of New England snow is sometimes called “poor man’s fertilizer”. If you have veggie garden beds, piling excess snow on them might be a great way to help your soil build up the nutrients it needs for gardening season.

Let it Snow!

Snow can be a pain, but it can also be fun, interesting, and a way to learn more about how your garden fits into the world around it. Whether you’re from a place that gets regular snow or a Louisiana gardener dealing with a first-time snowfall, we hope you and your garden are safe and healthy during this winter weather!